The injections are to lubricate the joint and help the healing process following the surgery the pitcher had on both knees in the offseason. ... The shots will be administered over a two-week period, though it's unclear when they began.

[T]here was some suggestion that such treatments are relatively unusual for athletes. Joint lubricants known as Hylan typically are used in older people with arthritis or osteoporosis, according to Web sites dedicated to the topic. According to the same sites, Hylan contains synovial fluid, which serves as a lubricant in joints like the knee.